Hi Robert. Firstly, I must echo what all the others have focused on ... the tracks. You´ve made a great job of them and the running gear. But apart from the mud around the lower hull, there doesnt appear to be any other weathering. Maybe because you´re not totally finished yet??
The camo looks great, but needs some filters to tie it together a little more and cut down on the "showroom" glare (IMO). As JGags has already pointed out, the barrel needs some weathering as well.
Its great to see a Sturmtiger again ... havent seen one of these modelled for some time.